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| United States Patent |
5,090,457
|
|
Corain
, et al.
|
February 25, 1992
|
Electro magnetic weft selection device
Abstract
Device for selection and presentation of the weft yarns for high-speed
looms, in which the mechanism of selection of the weft yarns comprises a
set of collars, each equipped with an iron armature. The collars are slid
through a free end of selectors and cooperate with a transverse lifting
beam as well as with a corresponding set of permanent magnets equipped
with a coil in order to nullify the magnetic field generated by the same
magnet.
| Inventors:
|
Corain; Luciano (Venice, IT);
Maitan; Gianni (Venice, IT);
Corazzola; Luigi (Tres, IT)
|
| Assignee:
|
Nuovopignone-Industrie Meccaniche e Fonderia S.p.A. (Florence, IT)
|
| Appl. No.:
|
542812 |
| Filed:
|
June 22, 1990 |
Foreign Application Priority Data
| Jun 30, 1989[IT] | 21036 A/89 |
| Current U.S. Class: |
139/453 |
| Intern'l Class: |
D03D 047/38 |
| Field of Search: |
139/453,455
|
References Cited
U.S. Patent Documents
| 4438791 | Mar., 1984 | Oesterle et al. | 139/453.
|
| 4556089 | Dec., 1985 | Juillard | 139/453.
|
| 4852618 | Aug., 1989 | Zollinger et al. | 139/453.
|
Primary Examiner: Falik; Andrew M.
Attorney, Agent or Firm: Morgan & Finnegan
Claims
We claim:
1. A device for selection and presentation of weft yarns for high-speed
looms, which device comprises a set of fingers having eyelets through
whose eyelets the weft yarns run, which set of fingers are hinged to a
corresponding set of actuation levers which are angularly moved by a
corresponding set of selectors, said selectors being elastically urged
against a lever means operated by an oscillating element, and a transverse
lifting beam being provided in order to simultaneously lift all of said
selectors at a selection cycle, said device further including a set of
collars for the selectors, said collars being equipped with an iron
armature, which collars slidingly support a free end of said selectors and
cooperate with a corresponding set of magnetic means each equipped with a
respective winding, with which magnetic means said collars are brought
into contact by the transverse lifting beam and remain magnetically
attached to said magnets in a lifted position, with the selection and
hence the lowering of the selector being achieved by nullifying the
magnetic field generated by the respective magnetic means by causing an
electrical current to flow through said winding.
2. A device for selection and presentation of the weft yarns for high-speed
looms according to claim 1, wherein said armatures are magnetic with the
selection, and therefore the lowering of a selector being achieved by
magnetic repulsion, by creating with the magnetic means a magnetic field
of polarity opposite to the polarity of said magnetic armature.
Description
The present invention relates to a novel device of selection and
presentation of the weft yarns. The novel device eliminates the use of
program-controlled feeler needles and reduces the moving parts and
consequently the number and energy value of the impacts. This enables a
rational, effective, reliable and cheap operation of the device to be
accomplished even at such high speeds as required by the modern looms.
BACKGROUND OF THE INVENTION
Several types of devices of selection and presentation of the weft yearns
are already known.
According to one of these prior art devices a set of fingers, through whose
eyelets the several weft yarns run, are hinged onto a corresponding set of
actuation levers. The actuation levers are urged by a respective return
spring against a stroke limit and are angularly moved by a corresponding
set of selectors hinged to them. The selectors are urged by a respective
return spring against a corresponding set of feeler needles of the weft
yarns selection mechanism. The selectors can be shifted by a transverse
oscillating beam supported by a cam-driven "L"-shaped lever which is urged
against said cam by a return spring and cooperates with suitable
appendices provided on all of said selectors. A further transverse beam is
provided at the end of another--also cam-driven and spring returned--lever
in order to simultaneously lift all of the selectors at each selection
cycle.
In the presence of a selection hole in the perforated-tape or
hole-closing-electromagnet mechanical program, the relevant feeler needle
penetrates said hole, consequently moving downwards. Due to the effect of
its return spring, the respective selector moves downwards and comes thus
to a position in which it interferes with the movement of said oscillating
beam. Such an interference will cause an oscillation of the same selector,
and consequently of the respective actuation lever to take place,
consequently causing an angular shift of the relevant arrow which will
present its own, so selected, weft yarn, to the weft inserter organ.
Unfortunately, such a structure suffers from a plurality of mechanical
drawbacks which are substantially due to the weft yarns selection
mechanism The weft yarn selection mechanism with its feeler needles shows
a poor precision at high speeds, and is extremely sensitive to dust, to
moisture and to all changes in atmospheric conditions, which may cause the
blocking thereof. On the other hand, said selection mechanism, with its
moving parts, is subject to considerable wear and a consequent short
useful life.
SUMMARY OF THE INVENTION
The purpose of the present invention is of obviating the above said
drawbacks and to provide a device of selection and presentation of the web
yarns, which employs a weft yarns selection mechanism which does not use
feeler needles and contains reduced moving parts.
This objective is substantially achieved in that the free end of each
selector is coupled with a collar equipped with an iron armature. The
collar, in cooperation with said transversal lift beam, is brought into
contact with a relevant magnetic means, such as a permanent magnet
provided with a winding, to which magnetic means said collar remains
magnetically attached, thus keeping the respective selector in its lifted
position. The latter is selected and hence lowered by simply causing an
electrical current of a precise value which is suitable for nullifying the
magnetic field generated by the same magnetic means to flow through said
winding provided on said magnetic means.
In such a way, the device no longer contains mobile elements (i.e., the
needles) which have to penetrate holes. Additionally, a considerable
reduction is achieved in the moving parts, because at each cycle the only
moved element is the selected element, with all of the other elements
remaining stationary. The number and energy of impacts, and therefore the
wear, of the various elements, is consequently reduced. The required
energy is minimized since the only strictly necessary energy is for
nullifying the magnetic element of the only selected element.
Summing up, the present device of selection and presentation of the weft
yarns for high-speed looms comprises a set of fingers which are hinged to
a corresponding set of actuation levers that are angularly moved by a
corresponding set of selectors. The actuation levers are elastically urged
against a selection mechanism and are moved via an oscillating element.
According to the present invention, the selection mechanism comprises a
set of collars each of which are equipped with an iron armature and which
slidingly support the free end of the selectors and cooperate with a
corresponding set of permanent magnets. Each permanent magnet is equipped
with a respective winding with which permanent magnet said collars are
brought into contact and remain magnetically attached in a lifted
position, by the transverse lifting beam. The selection and, hence, the
lowering of a selector is achieved by nullifying the magnetic field
generated by the respective permanent magnet by causing an electrical
current with a precise value of intensity, and in a well defined flowing
direction to flow through said winding.
According to a variant of the present invention, the collars are equipped
with a magnetic armature and cooperate with electromagnets suitable for
generating a magnetic field whose polarity is opposite to the polarity of
said armatures.
In this case, it is no longer required that the electrical current is of a
specific, exact value necessary to nullify the magnetic field generated by
the permanent magnet. The value of said electrical current can be further
reduced since an extremely small electromagnetic field is now necessary in
order to repel the magnetic armature of the collars.
The invention is better understood by referring to the hereto attached
drawings. The drawings illustrate a preferred form of practical embodiment
and are given for exemplifying purposes, and in no way should be construed
as being limitative of the present invention. Technical, technological or
structural variants may always be supplied without departing from the
scope of the same invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a partial perspective view of the lefthand end of a loom
wherein the weft yarns selection and presentation device according to the
present invention is shown;
FIG. 2 shows a side sectional, enlarged-scale view of the weft yarns
selection and presentation device of FIG. 1, during the initial step of
the selection cycle with all of the fingers being in their lifted
position;
FIG. 3 shows a view analogous to the view of FIG. 2, during the step of
selection and presentation of a finger;
FIG. 4, shows a view analogous to the view of FIG. 3, during the step of
selection cycle end, when the selected finger is caused to return back to
its resting position, and the relevant selector has been lifted by the
lifting beam. FIG. 5 shows a variation of the device shown in FIG. 2.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to the figures, the stationary bobbins 1 are shown in schematic
form, from which the weft yarns 2 are drawn and run through the eyelets 3
of the fingers 4, 4.sup.i, 4.sup.ii, . . . 4.sup.vii of the selection and
presentation and device 5 remain sticking to the side edge 6 of the cloth
7. When the weft yarn 2.sup.i is presented, the lowering of the respective
finger 4 (see FIG. 1), in front of the weft inserter 8, the yarn is hooked
by this latter and, dragged by the movement of the weft inserter onto the
slay 9 of the loom in the stroke direction 10, is inserted inside the open
shed formed by the warp yarns 11 and 12, and is picked by the comb or reed
13 against the front edge 14 of the fabric 7.
The selection and presentation device 5 is fastened onto the breast beam 15
of the loom on the left-hand end thereof, and comprises a case 16 having
within its interior an inwardly protruding portion 17 which constitutes a
stroke limit for a set of actuation levers 18, 18.sup.i, . . . 18.sup.vii
(in FIG. 3 only two of these levers are visible, in that the residual six
levers are overlapping with 18.sup.i). Said shaft 19 supported by the case
16 and are respectively urged against said protruding portion 17 by
springs 20, 20.sup.i, . . . 20.sup.vii (only the first spring is visible
in the figures; the residual seven springs are overlapping) and have
hinged to them by means of the pivots 21, 21.sup.i, . . . 21.sup.vii,
fingers 4, 4.sup.i, . . . 4.sup.vii which are guided in their lowering
movement by a guide box 22 which is solidly affixed to the case 16.
The selectors 24, 24.sup.i, . . . 24.sup.vii are hinged onto said actuation
levers 18, . . . 18.sup.vii by means of respective pivots 23. Said
selectors 24, 24.sup.i, . . . 24.sup.vii are urged downwardly by springs
25 acting between an end of the same selector, and anchoring 26 purposely
provided on the relevant actuation lever. Each selector 24, 24.sup.i, . .
. 24.sup.vii is provided with a shoulder 27, 27.sup.i, . . . 27.sup.vii
suitable for cooperating with the oscillating transverse beam 28.
Transversal beam 28 is supported by an "L"-shaped lever 29, which is
hinged at 30 and is constantly kept by a spring 31 into contact with a cam
32 driven by the driving shaft 33. Driving shaft 33 also actuates the
cutting device 34 of the loom (see FIG. 1).
A collar 36, 36.sup.i, . . . 36.sup.vii is slid onto the free end 35 of
each selector 24, . . . 24.sup.vii and said collar being guided by a guide
block 37 and is equipped with an iron armature 38, 38.sup.i, . . .
38.sup.vii hinged thereto. The collar cooperates with a further transverse
lifting beam 39 provided at the end of another lever 40 which is hinged at
41 and which is kept urged by a spring 42 against a second cam 43 integral
with said driving shaft 33, as well as with a permanent magnet,
respectively 44, 44.sup.i, . . . 44.sup.vii. A winding 45 is provided
which can be closed on its own demagnetizing circuit 46 through the switch
47 governed by electronic programmer, not shown in the figures.
The device according to the present invention operates as follows.
At the beginning of the selection cycle all of the switches 47 are open and
all of the collars 36, . . . 36.sup.vii, lifted by the transverse lifting
beam 39 due to the effect of the cam 43, have their iron armatures
38.sup.i, . . . 38.sup.vii magnetically hooked to the relevant permanent
magnets 44, . . . 44.sup.vii and hence keep the respective selectors 24, .
. . 24.sup.vii out of the oscillation range of action of the oscillating
transverse beam 28, as shown in FIG. 2.
When, for example, the finger No. 4 has to be selected, the electronic
programmer closes the relevant switch 47 causing the de-magnetization of
the magnet 44 to take place and liberates the collar 36. Due to the effect
of the spring 25, collar 36 moves downwardly together with the relevant
selector 24 which will thus enter within the range of action of the
transverse beam 28. By oscillating from its position shown in broken lines
as indicated by the reference numeral 29 in FIG. 3 to its position shown
in solid lines and indicated with the reference numeral 48, transverse
beam shifts to the right the same selector by acting on the shoulder 27 of
this latter, thus causing the actuation lever 18 to rotate clockwise and
the finger 4 (see still FIG. 3) to be lowered.
Thereafter, the end step of the selection cycle is performed. Due to the
effect of the cam 32 and of the spring 31, the transverse beam 28 returns
backwards together with the lever 18 and with the arrow 4 due to the
effect of the spring 20, after which the selector 24 and the relevant
collar 36 are lifted by the transverse lifting beam 39 by the effect of
the cam 43 (see FIG. 4), and the switch 47 is opened, with the starting
conditions shown in FIG. 2 being thus restored.
Finally, according to a variant of the invention shown in FIG. 5, which
does not substantially modify the operation of the present invention, said
armatures 58, 58.sup.i, . . . 58.sup.vii of said collars 36, 36.sup.i, . .
. 36.sup.vii are magnetic and 54, . . ., 54.sup.vii are electromagnets,
whose energizing circuits 46 are used to generate a magnetic field with a
polarity opposite to the polarity of said magnetic armatures.
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